February 3, 2006
Engine and Transmission Mounts

The engine and transmission mounts are now fabricated and installed in the car. Many thanks to John Grimberg, machinist extrodinare who came up with the idea for the transmission mount and designed and fabricated it and the engine mounts. The engine mounts are essentially identical to the Caterham SV mounts for the Focus engine, just sized a little larger and to fit the Miata engine.

Passenger side Driver side

The tailshaft housing on the right is the prototype butchered to fit with a sawzall, die grinder and file. The one on the left is a stock housing and the one in the middle is the machined piece.

Left is the machined piece that is bonded and bolted to the transmission after cutting away much of the original power plant frame mount. Right is another view from the rear.

The Caterham/Sierra T9 trans mount bolted to the intermediate piece and the tailshaft housing.

We made the motor mounts 1/4" taller than we measured, not knowing how much give there would be when the weight of the motor was finally allowed to rest on the mounts. The weight of the engine dropped the height 1/8" leaving clearance to the nose cone a little tight. I will shorten the outer ends of the engine mounts a bit to get a little more clearance.

The car is now on the floor with the engine and trans supported by the new mounts. Ground clearance under the oil pan came out at 4 1/4" but will lose 1/8 to 1/4" when I shorten the engine mounts. It looks like I may not have to shorten the oil pan after all although it would be easy to cut 1" out of the pan and extend the sump forward to make up for lost capacity. I am also considering an accusump to protect the engine under hard cornering loads.

Views from the front of the car and looking down at the transmission as it disappears into the tunnel. The bosses on the sides of the transmission case had to be filed down to allow the trans to fit far enough into the tunnel.

A little more fit and finish work on the mounts and I can powder coat the engine mounts and get on with the plumbing and wiring. A major milestone has been achieved!

Feburary 4, 2006

I removed the engine mounts and using a belt sander, removed 1/8" off the bottom of the outer end of the mounts. I also removed the rear vacuum fitting and now everything fits fine and I have 4 1/8" clearance under the oil sump. I am leaning towards modifying the pan anyway, 5+ inches of clearance sounds good to me even though my lowered Miata has less. The Miata pan is somewhat protected by the subframe, the Caterham pan is hanging out the all by itself.

The start of this project is here